I have 3 FN's and they are actually about the same money the QC mansions costs by the time you get the wheel, shelves, pan, etc. I think it cost me about $100 bucks to customize my FN's, bringing the total of the cage to around $280. I only got 1 pan so that was around $20, the wheel was $60, and the shelves that I made myself were about $20.
It's all a matter of personal preference. You can't say there is one cage out there that is the best of chinchillas, because many cages can be customized to be the best for the specific owner. IMO, FN's are the best, hence why I have 3. The full front opening doors allows for you to easily reach the chin, easily reach all corners of the cage to clean or hang accessories, and I love the overall look to them. QC cages look a bit too industrial for me.
But then you will have the QC fans who will rave about the QC cages. They're just not for me.